A recent magnetic head assembly includes a suspension spring in the order of 15 mm×20 mm and a slider of several to 1 mm square provided in a top portion of the suspension spring, in which a gap between a thin film magnetic head and a magnetic disk is reduced to in the order of several to 10 nm.
The performance tests of the magnetic disk as an information recording medium of HDD and the magnetic head (magnetic head assembly) for writing data on the magnetic disk and reading data from the magnetic disk are performed precisely by respective testers in the manufacturing steps.
In order to improve the test efficiency of the magnetic disk or the magnetic head, JP-A-2001-52319 and JP-A-2006-179107 describe a tester having a plurality of test decks and processing signals from the magnetic heads by distributing signals from the test decks between the test decks or selectively switching the test decks.
The magnetic heads are tested by the magnetic head tester with a unit of magnetic head assembly and the magnetic head assembly, the magnetic heads of which are tested, is switched to a new magnetic head assembly after the test is ended. The switching is made by handwork at present.
The test is interrupted during the switching of magnetic head and the measuring portion which receives a read signal from the magnetic head becomes standby state. Therefore, the test efficiency of the magnetic head assembly is dropped. On the other hand, the size of magnetic head assembly is reduced and a mounting of a magnetic head assembly on a head clamp table of a head carriage (which is performed by using a mounting hole (a protruded edge portion) of the magnetic head assembly). Further, a demounting working efficiency of the magnetic head assembly is low and, therefore, through-put of the head test depends on the switching work of the magnetic head assembly.
Under the circumstance, the switching operation of magnetic head assembly may be automated. However, up to now, the test of magnetic head assembly must be performed by contacting a probe of a contact probe unit with a terminal pad of a flexible printed circuit board (referred to “flexible cable” hereinafter) connected to magnetic heads.
About 6 probes (pogo pins) are provided in the contact probe unit. However, in a case where the flexible cable is curved or bent when the magnetic head assembly is set on the head clamp table of the magnetic head tester, the flexible cable can not electrically contact with the contact unit.
The flexible cable extends rearward from a mounting base of the magnetic head assembly and has a front end portion in which a magnetic head is provided and a rear portion on which a terminal pad is provided. The terminal pad is mounted on a terminal pad pedestal provided below the contact unit. However, the terminal pad tends to curve upward by wind generated by rotation of a disk positioned in the magnetic head clamp table or in the vicinity thereof before it is mounted on the terminal pad pedestal. Further, even in a case where the terminal pad is mounted on the terminal pad table, there is a problem that the terminal pad is floated and flatters due to the wind.
In order to automate the exchange operation of magnetic head assembly, it is necessary to transport the magnetic head assembly to the head clamp table with using a handling robot and to mount a magnetic head assembly on the head clamp table. However, even when the magnetic head assembly is mounted, the terminal pad is curved upward due to wind caused by the magnetic disk and can not be mounted on the terminal pad pedestal. In such case, it is impossible to ensure the contact of the terminal on the terminal pad with the probe of the contact probe unit. Therefor, there is a problem that the test of magnetic head can not be performed automatically.